Electrostatic damage, leakage, the chip itself issues, silver line on welding, electrostatic breakdown leakage during transport, package time debugging or encapsulated think product leakage.
Conclusion throughout the Web, most LED leakage attributed to electrostatic damage. They proposed solutions emphasize ESD measures. It makes packaging plant and users is very difficult. Because even if they do the anti-static measures, LED leak will still be there. Then, LED the leakage causes what is it? I think that at the moment, light emitting diode leakage reason most likely is the following (sorted by probability):
1, chip received the tainted (the most important and most issues)
2, high silver
3, wire welding
5, improper use of
6, the chip itself leakage
7, improper chip crack